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Fleas: Diagnosing, Treating, Preventing

Fleas are a huge problem once they find their way into your home, and they can easily hitch a ride on pets or even your clothing after hopping on from the yard. These tiny, wingless insects feed on the blood of their hosts, causing enough irritation and itching to plummet your household into a scratching frenzy! These blood-feasting parasites can do far more damage than just making us and our pets itch. Fleas carry diseases, and they can cause serious health problems for dogs and cats. But what’s the best way to get rid of fleas? Removing fleas from your dog is a multi-step process that requires medication, bathing, and lots of vacuuming.

How to Diagnose Fleas on Dogs

If your dog has been scratching (especially behind the ears) and biting at their skin (especially around the rear), fleas may be present. The first step in treating the issue is to confirm the presence of fleas and rule out other possible reasons your dog is scratching. It can be difficult to find fleas on your dog or cat. It’s more likely you’ll be able to spot signs of fleas, like “flea dirt” that shows up on the skin in places where the little bloodsuckers have been feeding. Flea dirt is actually flea feces. Where there is flea dirt, there either is or has been fleas.

Flea Dirt

Pro tip: use a flea comb to search for little black specks on your dog’s skin, typically around their rear end or head. The fleas will be little wriggling black dots that jump, and flea dirt will look like coffee grounds. If you spot either, contact your vet.

Eradicating Fleas

There are countless products on the market that promise to treat your dog for fleas but getting rid of a full-blown flea infestation is a multi-step process that can take weeks or even months depending on the severity. This is why prevention is so important. Giving your pet a monthly flea and tick preventative is much easier than trying to get rid of fleas once they’ve invaded your home.

Flea Comb

While an effective medication can start killing adult fleas in a matter of hours, you’ll still need to perform daily flea checks using a fine-toothed metal flea comb to remove them at every stage in their life cycle. This isn’t a regular brushing, since the goal of using a flea comb is to knock the parasites off your dog.

Flea Combs pull Fleas and Flea Dirt from the fur

Serious infestations will require continued sessions with the flea comb to ensure all eggs are removed from your pet, so set an alarm on your phone to remind yourself when it’s time for Fido’s daily flea check. Ask your vet if you have questions about how to use a flea comb or how often you should perform flea checks, once your dog is on a regular preventive schedule.


Several types of flea medications are designed to kill the fleas feasting on your pet. These are administered in different ways, and some offer combined protection against several other parasites in addition to fleas, such as ticks, heartworm, hookworm, and tapeworm. Your vet can help determine the best medication for your dog depending on their health, size, and the level of infestation.

Oral Flea Medications

Oral prescription flea prevention medications are the gold standard for treating dogs for fleas. These medicines come in chewable tablets that work quickly and efficiently, usually within the first 30 minutes to a few hours after administration. Some of the oral medications used to kill and prevent fleas are:

Your vet can help you choose an oral flea and tick medication that will keep fleas from coming back, and provide protection against tick-borne illnesses as well.

If you’re in a pinch and need a quick flea treatment (for instance, if you’re caring for a stray or the vet clinic is closed), Capstar® is an oral flea medicines that are available without a prescription. Both medications will work quickly but only kill adult fleas, meaning monthly flea prevention will still be needed to control infestations but these medications may provide temporary relief.

Topical Flea Medications

Topical flea and tick preventions can also be very effective, but the liquid application is more difficult to apply and takes longer to start killing fleas (between 12–48 hours). These are applied on the back of your dog’s neck to keep them from ingesting the medication while it’s still wet. Be sure to allow all topical medications to fully dry before allowing the dog around other pets (such as cats) or small children in the household.

Prescription options like the following should be effective:

Natural Flea Medications

Stay away from using flea treatments that claim to be natural or homeopathic. So-called natural flea treatments are not proven to work effectively against fleas, and they can even be dangerous for dogs, or further irritate their already-itchy skin. Homeopathic methods are not FDA approved or regulated, which means these are often ineffective at best or harmful in worse situations. An FDA-approved flea medication is your best bet in protecting your pet against fleas. There are no ‘natural’ products that will prevent fleas on dogs. Some popular claims about natural flea treatments include ingredients like garlic, which is toxic for dogs and very harmful, if consumed.

Some flea medications, like Simparica, are derived from a natural molecule found in dirt. Pet parents who are searching for a more natural option—than some of the other products—can ask their vet about whether Simparica is right for their dog.

Dog Flea Shampoo and Sprays

Along with a prescription medicine, flea shampoos and sprays can help get an active flea problem under control and bring your dog quick relief. As you bathe your dog, use a flea comb in the bath to remove any flea dirt or eggs from their coat.

Active ingredients in medicated flea shampoos are designed to kill the parasites that are on your dog instantly, but won’t necessarily provide lasting protection against reinfestation later. Combining a prescription-strength oral flea medication with a medicated shampoo or spray will achieve instant relief, along with long-term preventative power.

Treating Your Home for Fleas

Just as you carefully treat and remove fleas from your pet, you’ll also need to clean your home frequently, vacuuming at least every other day. Room sprays, powders, and other products may be used in combination with medication to help eliminate fleas and flea eggs in the places your dog hangs out. Proceed with caution, as these products can pose serious threats to your health and the health of your pets if the instructions are not precisely followed. Look for products designed to kill fleas in the home and yard that won’t harm pets, such as:

Getting rid of all flea dirt, fleas, and flea eggs from your house requires several days of cleaning. Vacuum all upholstered furniture (couch, chairs, mattress) and all floors, carpets, rugs, and baseboards to remove eggs that fall off pets and lodge in crevices. Carefully empty the vacuum each time you finish into a sealed bag and dispose of the waste far from your house in an outside rubbish bin. Frequently wash any pet bedding on hot and dry on high heat or in direct sunlight.

In the opinion of our doctors, your best bet is to opt out of do-it-yourself treatments for your home and yard and to instead enlist the help of a professional exterminator. This is foolproof, although more financially costly.

Prevention of Fleas on Dogs

While it’s possible to get rid of fleas once they’re in your home, the best way to fight off fleas is to stop them before they start infesting. Battling a flea infestation requires lots of time, energy, money, and attention to keep eggs from hatching and reinfesting. Keeping your dog and home flea-free requires regular preventative medication that works continually to protect your pet from the inside out. Using year-round flea, tick, and heartworm medicine is essential to keep these pests from harming your pet.

Though fleas tend to be more common during warmer seasons and in humid climates such as our state of South Carolina, most vets recommend having your dog on a flea and tick preventative throughout the year to protect them at all times—especially if they’re prone to allergic reactions to flea bites (known as flea allergy dermatitis). For most dogs and cats, preventatives can be purchased in 6 month or 12 month boxes, taking the guesswork out of giving the monthly meds. Talk to your vet to determine what type of flea and tick prevention is best for your dog, since they’ll be able to make a recommendation that’s right for your needs.


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